Rotary pump of the liquid ring type with side channels



P. LAHTI Oct. 3, 1961 ROTARY PUMP OF THE LIQUID RING TYPE WITH SIDE CHANNELS Filed May 21, 1959 United States atent 3,002,463 I ROTARY PUMP OF THE LIQUID RING TYPE WITH SlDE CHANNELS Patter Lahti, 'Iikkurila, Finland Filed May 21, 1959, Ser. No. 814,840 Claims prio 'ty, application Finland Apr. 10, 1959 11 Claims. (Cl. 103-96) This invention relates to rotary pumps.

An object of this invention is to provide an improved rotary pump of the liquid ring type with side channels,

including a cover structure, furnished with a liquid space and connected with a discharge passage. The inner wall of the'inner part of the cover structure and the pump body build together .the pump housing.

Characteristic of this pump is that an outer groove, approximately arcuate is formed on the inner wall of the inner part of the casing, one end of which groove communicates with a liquid inlet port and a suitably shorter inner groove, also approximately arcuate, is positioned nearer the shaft of the pump, communicating with the liquid space disposed within the casing through the outlet port. Near the center of this liquid space is situated an opening to the discharge passage of the pump.

' The invention is next explained in detail with reference to the attached drawing in which:

FIG. 1 is a sectional view of the pump of the invention taken along line II in FIG. 2.

FIG. 2 is a sectional view along line II-II in FIG. 1.

FIG. 3 illustrates the casing of the pump without its inner part and in a direction corresponding to FIG. 2.

FIG. 4. is a sectional view along line IV-IV in FIG. 3.

.FIG. 5 is a sectional view along line V V in FIG. 3.

FIG. 6 illustrates the inner part of the casing from the same side as FIG. 2.

FIG. 7 is a sectional view along line VlI-VII in FIG. 6.

FIG. 8 is a sectional view along line VIII-VIII in FIG. 6.

FIG. 9 is a sectional view along line IX--IX in FIG. 6.

In the drawing, the reference number 1 indicates the body of the pump, to which the casing 2 is fastened with screws 4 inserted into holes 3. A separate inner part or case 5 is fitted tightly into the outer casing. An annular gasket'6 is placed in a grooveand islocated between the body 1 and the case 5. Between the body 1 and the case 5 is the pump chamber 7, in which a bladed rotor 10 is fastened onto a shaft 8 with a key 9. Around the shaft 8 is a packing ring 11 on the internal wall of which there are two grooves parallel to the shaft 8 which do not appear in the drawing. These grooves are engaged by projections 12 and 13 fastened on the shaft 8 and loosely fitted to the packing ring 11. Around the shaft 8 and against the packing ring 11 has been fitted an annular member 14, which is suitably of rubber or of any other resilient material. This member is pressed by a spring 15 against the packing ring 11. One end of the spring 15 rests against the ring 16 fastened tightly onto the shaft 8. Actuated by the spring 15 the packing ring 11 is pressed against the ring 17, fastened onto the pump body 1 by brazing, welding or in any other suitable way. When the pump rotates, a seal is obtained along the contacting surfaces of the packing ring 11 rotating with the shaft 8 and the stationary ring 17.

The outer edge of the pump chamber 7 is connected with the seal space 18 through a passage 19 which leads the liquid under pressure from the outer edge of the pump chamber 7 into the seal space 18 when the pump rotates. Thus the liquid eliminates the air from the seal space 18, thus developing pressure which improves the seal. Further, the liquid acts as a lubricating agent between the packing ring 11 and the stationary ring 17 for decreasing friction. The liquid also tends to remove foreign matter from the seal space 18 such as might accumulate after extended use of the pump.

In the casing 2, there is a suction passage 20 extending into the case 5 and opening through a flat suction inlet 21 to the pump chamber 7. At the inlet 21 begins an arcuate groove 23, fluid movement being indicated by the arrow 22 which is pointed in the direction of rotation. The suction passage 20 is narrower towards suction inlet 21 and the suction groove 23 becomes wider on the side of the outer perimeter of the case 5.

Further, the case 5 has another groove 24 which is nearer the shaft 8 than the suction groove 23. This second groove 24 is hereafter called the discharge groove. Between the suction groove and the discharge groove is a rather narrow ridge 25. The end of the suction groove 23 is shaped to be slightly shallowing. The discharge groove 24 is shaped to be slightly deepening in the direction of rotation as shown in FIG. 9. The discharge groove 24 continues as a pipe 26 through the case 5 and ends at the inlet 28, leading to the liquid space 27 of the casing 2.

In the center of the bottom 29 of the liquid space 27 is an opening 30 which leads to the discharge passage 31. In the bottom of the liquid space 27 is a drain hole 39 to be closed by a plug 32. The liquid space 27 communicates with the pump chamber 7 also through a hole 33 (FIG. 2) in the bottom of the suction groove 23, near the suction inlet 21. In the case 5 is a bore 34 (FIG. 1) forthe end of the shaft 8. Connected with the suction passage 20 is a filling inlet 35 (for the pump) to be closed by a plug, not shown in the drawing. At the end of both suction and discharge passagesthere are common flanges 36 and 37 for connecting the pump with a pipe system.

If the pump is empty before being started, it must first be filled with the liquid to be pumped through the inlet 35. When the pump has been started, the liquid in the pump chamber 7 begins to rotate since it is actuated by the bladed rotor 10. Thus, in the pump housing 7, aretating liquid ring is formed which extends from its inner edge to the outer edge of the discharge groove 24. The rotation of the liquid ring in the pump housing creates a suction at the inlet 21 in accordance with Bernoullis law, and induces air to flow from the suction passage 20 and the connecting suction pipe through the inlet 21 into the liquid in the liquid ring. Owing to centrifugal force this air, however, will very soon separate from the liquid ring and will move towards the interior of the ring and be discharged through the pipe 26 and opening 28 to the liquid space 27. With this air some liquid will enter into the liquid space.

Because the discharge groove 24 is arcuate, both the air and liquid begin to rotate in the liquid space 27. The liquid is thus pressed towards the outer perimeter of the liquid space and the air in the mixture moves to the center of the liquid space 27. The liquid will partly flow back through the hole 33 into the pump chamber 7 whereas the air will flow into the discharge pipe 31 through the opening 30 in the center of the liquid space 27 In this way all air will be evacuated from the suction pipe 20 after which the pump begins to operate as a liquid ring pump.

Owing to the fact that the suction inlet 21 is near the outer perimeter, the flow speed of the liquid in the liquid ring is high at this point and therefore the suction is very efifective, and, in fact, more eifective than it would be if the suction inlet 21 were nearer the center. The suction at this inlet is further improved by the fact that the bottom of the part in the suction passage 20 which is in the case 5 and is furnished with a cover 38, continues without changing direction in the form of the bottom of the suction groove 23. Owing to the powerful suction which results, the air in the suction pipe will be sucked into the pump and discharged into the discharge pipe very effectively and quickly. The pump is therefore selfpriming up to over 8 meters and the air in the suction pipe can be evacuated in a few seconds. Thus the pump is useful especially in cases when the operation involves frequent starts and stops. Because the suction passage 20 and the suction groove 23 are reduced at the suction inlet 21 at the outer perimeter of the case 5, the back flow of the liquid into the suction passage is almost impossible when the pump rotates. No valve is therefore required in the suction pipe because of the efficient suction power of the pump.

After the pump is stopped there remains suflicient liquid in the pump chamber 7 and the liquid space 27 to enable the pump to be restarted without filling it through the inlet 35. This priming is necessary only if the pump has been emptied through the drain hole 39 or is empty for any other reason.

The casing 2 of the pump can be made of one or several parts, the latter case being shown in the drawing. In this case the manufacturing of the pump is much easier. A further advantage is that the inner part or case of the casing 2 can be readily interchanged with another and thus different pressures and capacities can be effected with the same pump.

The outer groove 23 is of uniform width from the suction inlet 21 in the direction of rotation to where the ridge 25 between the inner and outer groove begins. From there the groove gradually shallows towards its end. The inner groove 24, on the other hand, slopes to wards the opening 28. Thus the inclinations of the bottom surfaces of the outer and inner grooves are oppositely directed at the points where the grooves are side by side. This feature provides for a hydrodynamically favorable flow of the liquid from the outer to the inner groove.

The drawing and description are intended only to illustrate the idea of the invention. The invention may be varied in many different ways within the scope of the following claims.

What is claimed is:

1. A pump comprising a casing having aninternal chamber, a member fixed in said casing dividing said chamber into spaced sections, said member being provided with a peripheral inlet opening and with an arcuate groove opening into one of said sections and communicating with said peripheral opening, rotor means substantially coaxially aligned with said groove in said one section for circulating a medium received therein via said opening and groove, said member being provided with a second arcuate groove spaced radially inwards of the first said groove and with an opening communicating the second groove with the other of said sections, said casing being provided with a discharge opening substantially centrally positioned with respect to the second said groove.

2. A pump as claimed in claim 1 wherein said member is provided with an opening extending from the first said groove to said other section.

3. A pump as claimed in claim 1 wherein said chamber is substantially cylindrical, said grooves and chamber being substantially concentric.

4. A pump as claimed in claim 1 wherein the first said groove and peripheral opening have cross-sections which decrease at their connection.

5. A pump as claimed in claim 1 wherein the opening communicating with the second groove is an arcuate extension of the same.

6. A pump as claimed in claim 1, wherein said casing defines a seal space adjacent said rotor means, comprising a shaft extending through said casing and seal space and coupled to said rotor means; and, in said seal space, bearing means encircling said shaft and respectively fixed insaid casing and slidable on said shaft, and spring means on the shaft and urging the bearing means together to form a seal.

7. A pump as claimed in claim 6 wherein said casing is provided with a passageway connecting the seal space to said one section.

8. A pump as claimed in claim 1 wherein said memher is detachable from said casing.

9. A pump as claimed in claim 1 wherein said grooves are shaped in opposite rotary directions.

10. A pump as claimed in claim 1 wherein said members includes a ridge between said grooves.

11. A pump as claimed in claim 1 wherein the casing is provided with a vent opening in the bottom of said other section.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain Dec. 24, 1930 

